Lesson video

Hello, everybody.

This is Mr. James.

I'm happy to be with you here today to learn some science, and I hope you are feeling ready and rested and raring to go too.

Our lesson today is from the unit: Why we group and classify living things.

And the title of the lesson is this: Carl Linnaeus and Classification.

As a learning outcome, we would like you to be able to describe the work of Carl Linnaeus and his contribution to how we classify living things, and hopefully, after today's lesson, you'll feel plenty confident to do just that.

So let's begin.

We have some key words for our lesson, and I am just going to say those to you now.

You can repeat them if you like.

Scientist, organism, taxonomy, classify, and Carl Linnaeus.

Here are the meanings of those key words.

You can read them.

I'll put them on the screen.

If you need to come back to them later, you can.

Pause the video if you need to look at them for a little longer.

So this is what our lesson today is going to look like.

We are going to start with taxonomy, and then we'll talk about early classification, and then move on to talk about Carl Linnaeus himself.

Okay, here we go.

Taxonomy.

Scientists estimate that there are around 14 million different types of living things on earth today.

Imagine you've been given the job of sorting these organisms into groups.

Where would you start? You can pause the video and have a quick talk about that.

Taxonomy is the name for the area of science that focuses on naming, describing, and grouping living things.

Scientists who work on taxonomy are called taxonomists.

Here's a taxonomist observing a plant.

Sorting organisms into groups helps us to understand and learn more about newly discovered living things.

What does a taxonomist do? Is it A, describes, classifies, and names living things.

B, invents, builds, and engineers things.

Or C, counts, measures, and calculates things.

What do you think? Yeah, a taxonomist describes, classifies, and names, things.

Taxonomist look carefully at organisms and think about their observable characteristics when classifying them.

What are the observable characteristics of the organism below in these photographs? Have a chat about that.

You can pause the video now.

How did you get on? We can see that this organism has two legs, two wings, and a short tail.

It has feathers that are blue, black, yellow, and white.

It has a beak.

It's a predator.

It reproduces by laying eggs.

And it has more than one offspring at once, and it can fly.

Which of the following are observable characteristics? A, how many legs an organism has.

B, how old an organism is.

C, whether an organism lays eggs.

Or D, what an organism is called.

Take a moment to think about your answer.

Yeah, how many legs an organism has, we can observe that, and whether an organism lays eggs, yes, we can observe that too.

When they're classifying an organism, taxonomists don't just use photos, they make many observations of the living thing in its environment.

What questions do you have about this organism that could help us to classify it? Look closely at the picture, then discuss your ideas.

You might like to pause the video now.

Andeep says, is it warm blooded? Sofia says, does it have a skeleton inside its body? Laura, what is this organism's lifecycle? And Alex, is it a carnivore or an omnivore? This organism is called a blue tit.

Some children are talking about how to classify it.

Aisha, I think it's vertebrate animal because I know it has a backbone.

Izzy disagrees.

It can't be a vertebrate because it's a bird.

It has feathers, wings, and a beak.

What do you think? Pause the video now so you can have a quick talk about that.

I wonder if you are able to agree on some things, or maybe you had some differences.

Organisms can belong in more than one group.

Taxonomists organise groups for living things so that larger groups have smaller groups within them.

The smaller the groups get, the more in common each organism has with others in the group.

This helps us to see similarities and differences between living things.

The blue tit is an animal, it's a vertebrate, and it's a bird.

True or false? When we classify organisms, they can belong in more than one group.

What do you think? Take a moment to think about this.

Yes, it's true.

When we classify organisms, they can belong in more than one group.

Now, try and justify your answer.

Is it, do you think this because of A, that organisms can only belong in one group as they can't be an animal and a plant at the same time, or do you think B, organisms can belong in more than one group? A pigeon is an animal and it's a bird.

Take a moment if you need it.

Yeah, organisms can belong in more than one group.

A pigeon is both an animal and a bird.

The blue tip is part of the animal's group, which is actually very large and includes many organisms. Within that animals group, it is part of the smaller group, vertebrates, because it has a backbone.

And within the vertebrates group, it's part of the smaller group, birds.

It has lots in common with other organisms in this group.

Sam wants to create a branching key showing all the groups of living things that she knows about.

She'll start by dividing living things into large groups, and then dividing each of these groups into smaller ones until she's included all the different groups that she knows.

Which groups should she start with? What do you think? Pause the video now.

I'm pretty sure you had some interesting ideas there.

So how about this question? Which of these groups is it possible for an organism to belong to? What about A, micro-organisms and fungi.

B, insects and micro-organisms. C, animals and mollusks.

D, plants and ferns.

E, vertebrates and insects.

Which of these groups is it possible for an organism to belong to? Take a moment to think about this.

There's your answer.

It could be both a microorganism and a fungi, it could be an animal and a mollusk, and it could be a plant and a fern.

Now, we come to task A.

I'd like you to create a branching key showing all of the groups of organisms that you know about.

Your key might look like this, or it might have different branches.

You're going to need to pause the video to do this, so do that now.

Well done.

I wonder how many branches there were on your key.

Here's my work, says Sam.

Is it similar to yours? Pause the video so you can have a closer look at what Sam did.

How did you get on with that? Did you have lots of ideas like Sam? Looking at her branching key, we can see that she has split the organisms into animals, plants, and microorganisms. Sam knows three types of microorganisms, bacterial, viruses, and fungi, perhaps a little bit more about fungi.

For plants, interestingly, Sam seems to know more about non-flowering types of plants than she does flowering plants, even though there are more types of flowering plants.

So we have ferns, mosses, and conifers.

If we follow the line to animals, you can see that she's used the distinction between vertebrates and invertebrates to separate animals off there.

Under invertebrates, she knows about insects, mollusks, arachnids, and crustaceans.

And under vertebrates, she's remembered all five groups of the vertebrates.

Perhaps she remembered birds as a bit of an afterthought.

Interestingly, mammals doesn't go much further.

Perhaps, Sam ran outta time.

You might expect her to know a little bit more about types of mammals, especially as we're also a mammal, we humans.

She certainly came up with quite a few ideas, didn't she? I hope you did too.

Now, we move on to the second part of our lesson, early classification.

The natural world is very diverse.

Taxonomist have been working on the best ways to classify living things for a very long time.

Here, we see a taxonomist observing a plant.

The ancient Greek philosopher Aristotle, who was born in 384 BC or BCE.

He was one of the first people to write down his ideas about classifying organisms. Aristotle started with two large groups, plants and animals.

How is this different from the large groups that we've been using? Why do you think it's different? You can pause the video if you need to.

We have groups for plants, animals, and microorganisms. Aristotle did not include microorganisms because no one knew they existed yet when he was alive.

Microscopes wouldn't be around, they wouldn't be invented for another 1,900 years, so no one was able to make observations of microbes then.

Why didn't Aristotle have a group for microorganisms? Was it A, he didn't think microorganisms were living things.

B, he had no evidence that microorganisms existed.

Or C, he wasn't a very good taxonomist.

What do you think? Yeah, he didn't have any evidence that microorganisms existed.

Within his groups of animals and plants, Aristotle suggested some further groupings.

Land, animals that walked on the land.

Air, animals that can fly.

Water, animals that live in water.

Can you think of some living things that will belong in each of these groups? Pause the video now so you can discuss that.

I'm sure you had some good ideas.

What were the three groups that Aristotle split animals into? Was it A, land, B, underground, C, air, or D, water? Take a moment to think about your answers.

Split animals into land, air, and water.

This was a good start, but there were some issues with Aristotle's taxonomy.

For example, using his system, ostriches, snails, and guinea pigs would all belong in the same group.

What similarities are there between these animals? Pause the video for a moment while you have a discussion about that.

Did you find that a little bit tricky? I bet you did.

There's very little in common between these three animals.

They have different body coverings.

They do not all have a backbone.

They not reproduce in the same way.

They are not all warm blooded.

If a new land animal was discovered, we could not use similarities between these other land animals to learn more about it.

These animals have much more in common with the groups we classify them in now.

The ostrich is a bird.

The snail is a mollusk.

The guinea pig is a mammal.

What similarities are there between these animals and the other animals in their groups? Pause the video and talk about this.

Aristotle knew his classification system wasn't perfect, but it was the best that they had at the time.

Now, we have much better systems for classifying organisms because we have better equipment and can make more accurate observations of living things.

There is also better communication between scientists now thanks to modern inventions.

In Aristotle's time, if he wanted to share or discuss his ideas with other scientists that lived far away, he'd have to travel or write a letter that would be taken across the land in a chariot taking many days.

Now, scientists can use phones or the internet to instantly communicate with others across the globe.

Why was Aristotle's classification system not as useful as the one we use today? A, it was not written down for other scientists to reference.

B, there are not enough similarities between the animals in each group.

C, it didn't include microorganisms. Or D, it did not include plants.

Take a moment to think about this.

Yeah, there are not enough similarities between the animals in each group, and it didn't include microorganisms. Well done if you've got both of those right.

Time for task B.

Lucas has grouped some organisms according to Aristotle's classification system.

Group one includes a pigeon, a bee, and a bat, and group two, an orca, a salmon, and an octopus.

Explain why these living things have been grouped together using Aristotle's ideas about classification.

You might like to pause the video for a moment now while you do that.

Bee, pigeon, bat, these organisms have been grouped together because they can fly.

Aristotle would've classified them as air animals.

Salmon, orca, octopus, these organisms have been grouped together because they're all animals that live in the water.

Aristotle would've classified them as water animals.

List which groups the animals belong to using our current system of classification.

You'll need to pause the video for a moment to do that.

How did you get on? The bee, well, that's an animal, an invertebrate, and an insect.

The bird is an animal, it's a vertebrate, it's a bird.

The bat, well, an animal, a vertebrate, and a mammal.

The salmon, an animal, a vertebrate, and a fish.

The orca, an animal, a vertebrate, and a mammal.

And the octopus, an animal, an invertebrate, and a mollusk.

We're moving on now to the third part of our lesson today, and that is all about Carl Linnaeus.

Scientists continue trying to find better ways to group and classify organisms for centuries after Aristotle began.

In the 18th century, a Swedish scientist called Carl Linnaeus revolutionised the way we classify living things with his new ideas, influencing generations of taxonomists after him, and providing a system that is much more like the one that we still use today.

There, you see a painting of Carl Linnaeus.

I don't think that's his real hair.

Carl Linnaeus was born in Sweden in 1707.

Can you find Sweden on this map? There it is.

He was interested in living things from a very young age, and he was nicknamed the Little Botanist when he was just eight-years-old.

In 1732, Linnaeus embarked on a 3,000 mile-long research expedition to Lapland.

This is a picture of Lapland.

It's flatter than you might expect.

While there, he spent time making careful and detailed observations of plants and animals.

This helped him to come up with a system of classification that was based on more on shared characteristics of living things than Aristotle's was.

His new classification system included six groups for animals, and they were mammals, birds, amphibians, fish, insects, and worms. This new system was much more effective as it allowed scientists to see which organisms were related to others.

Over time, as more discoveries were made and better equipment enabled scientists to make more accurate observations of living things, this system has been developed into the groups we use now to classify animals.

Carl Linnaeus was a Swedish scientist who, A, invented classification, B, discovered microorganisms, C, created a better system for classifying organisms. What do you think? Yeah, it's C.

He created a better system for classifying organisms. Linnaeus also came up with a system for naming living things that was so effective that it's still in use today, over 250 years later.

Until Linnaeus' system, the same living things were called by different names in different places.

For example, this small crustacean can be called a roly-poly, a doodle bug, a pillbug, or a woodlouse depending on where you live.

I wonder what you call it.

There are also some different animals that were referred to by the same name.

Which of these is a daddy long legs, animal A or animal B? Depending on where you come from, it could be either.

Even when an attempt was made to standardise names using Latin, the language most often used by scientists at the time, there were still lots of confusing names.

This plant, for instance, and I'll need to take a deep breath here, was called viola floribus radicalibus corollatis apetalis seminiferis abortientibus caulinius, I think I said that right, which means short stemmed, free petaled, fruiting violet.

Linnaeus' system also used Latin but was much less complicated.

Binomial.

It's called that because it means two names, bi means two, and nomial means names.

What is the name for Linnaeus' system for naming organisms? Is it the uninomial system, that's A, the binomial system, that's B, or the trinomial system, that's C.

Can you remember? Yeah, it's the binomial system.

That was the name given to Carl Linnaeus' system for naming organisms. The binomial system gives all organisms a two part name, where the first part is the smallest group the organism belongs to, known as the genus, and the second part is the unique name for the species itself.

Do you want to have a go at saying this one first? Pause the video while you have a try at that.

Okay, I'll take a deep breath and see if I can do it.

Armadillidilium vulgare.

So this is the genus and this is the species, Armadillidilium vulgare.

Names used in the binomial system are always written in italics with the genus capitalised.

So we have tipula lunata, phalangium opilio.

Organisms with lots in common that belong to the same genus will have the same word for the first part of their binomial name, but every species has a unique second part.

Bellis perennis, bellis caerulescens, ursus maritimus, ursus americanus.

Which of the following is a binomial name for the organism below? What do you think? Is it A, monarch butterfly, B, orange butterfly, or C, danaus plexippus? Take a moment to think about that.

Yes, it's the third one, the one in italics, danaus plexippus.

For task C, choose a genus of organisms from the options below and carry out some research using secondary sources to find three living things that belong to that group.

So here, choose either panthera or canis.

You need to list their binomial name as well as their common name.

Here's an example.

Ursus maritimus, polar bear, ursus americanus, black bear, ursus arctos, brown Bear.

You'll need to pause the video.

Will you have a go at that? Great research.

Here's what Alex found out.

Are any of his findings the same as yours? Panthera tigris, tiger, panthera Leo, lion, panthera onca, jaguar, canis familiaris, dog, canis lupus, wolf, canis latrans, coyote.

Use the internet and books to find pictures now, pictures of each of the organisms that you've researched.

Carefully observe and identify as many similarities between the organisms as you can.

You'll need to pause the video now while you do that.

Here's what Alex found, tiger, lion, jaguar.

All of these animals look well adapted for hunting with sharp claws and teeth and strong legs for chasing prey.

They're all mammals with fur.

They have a similar shape to their face and features.

Dog, wolf, coyote.

All of these animals have pointed ears and a long nose.

They all have fur.

They have four jointed legs with paws at the end.

Their paws have claws.

Time to sum up what we've learned about Carl Linnaeus and classification.

The science of naming, describing, and grouping living things is called taxonomy.

Over time, scientists have been able to classify organisms more accurately.

Carl Linnaeus was a famous taxonomist who lived in the 18th century.

He improved the classification system for living things, and his system is still in use today.

Great research in the lesson today, well done.

And I will see you next time.

Goodbye.